摘要目的：合成靶向整合素αvβ6的光声成像及荧光成像的双功能探针。方法用吲哚氰绿‐羟基琥珀酰亚胺（ICG‐N HS ）与胱氨酸结肽反应生成 ICG‐结肽探针，用反相高效液相色谱仪（RP‐HPLC）分离出探针，质谱仪及光谱仪检测探针的分子量及最大吸收波长；光声成像仪及荧光成像仪检测不同浓度探针的光声信号及荧光信号；评估探针在激光照射下的稳定性；使用整合素αvβ6阳性和阴性的细胞进行细胞摄取实验，从而评估探针对整合素αvβ6的靶向性；评估光声成像及荧光成像所能检测到的最少细胞数。结果使用RP‐HPLC将ICG‐结肽从反应液中分离，保留时间为21.4 min ，质谱分析测得分子量为4727，荧光标记率为1∶1；光谱仪测得最大吸收波长为790 nm ；探针浓度与其光声信号强度呈线性相关，当探针浓度＜1.5×10－5 mol／L时，其浓度与荧光信号呈线性相关，光声成像与荧光成像能从背景中检测到的探针最低浓度分别为0.09×10－5 mol／L和0.05×10－5 mol／L ；对探针进行连续20次激光扫描，每次持续1 min ，其光声信号未见明显减退；αvβ6阳性A431细胞与αvβ6阴性293T细胞对ICG‐结肽探针的摄取在不同浓度及不同孵育时间均存在差异（ P ＜0.001）。加入5μmol／L未标记的结肽可以降低A431细胞对ICG‐结肽探针的摄取（ P ＝0.001）；光声成像和荧光成像可分别检测到低至0.4×106个和0.05×106个ICG‐结肽探针标记的A431细胞。结论靶向整合素αvβ6的光声成像及荧光成像的双功能探针具有良好的靶向性及敏感性，在αvβ6阳性肿瘤早期检测方面有潜在的实用价值。

abstractsObjective To develop a probe for photoacoustic imaging and fluorescence imaging targeting integrin αvβ6 . Methods The probe was separated by RP‐HPLC .Molecular weight and the maximum absorption wavelength of the probe were detected by mass spectrum instrument and optical spectrum instrument . Various concentrations of the probe were detected by photoacoustic imaging and fluorescence imaging . The stability of the probe was evaluated when exposed under laser . Targeting of the probe on integrinαvβ6 was evaluated in cell uptake assay with integrinαvβ6 positive and negative cells . The minimum number of cells that could be detected by photoacoustic imaging and fluorescence imaging was also evaluated . Results The probe ICG‐peptide was separated from reaction mixture by RP‐HPLC .The probe had a retention time of 21 .4 minutes and m/z of 4 727 . The labeling ratio of the probe was 1∶1 . The maximum absorption wavelength of the probe was 790 nm . The photoacoustic signal was linearly dependent on the concentration of the probe . The fluorescence signal was linearly dependent on the concentration of the probe when the concentration was smaller than 1 .5 × 10 -5 mol/L . The lowest concentration of the probe that could be detected above the background by photoacoustic imaging and fluorescence imaging was 0 .09 × 10-5 mol/L and 0 .05 × 10-5 mol/L ,respectively . No obvious decrease of the photoacoustic signal was observed after the probe was scanned 20 times ( each time lasted for 1 min) by laser . There existed&nbsp;differences ( P <0 .001) in cell uptake of the probe with various concentrations and reaction time between A431 cells (αvβ6 positive) and 293T cells (αvβ6 negative) . Cell uptake was inhibited by the addition of 5μmol/L unlabeled peptide in A431 cells ( P = 0 .001 ) . The lowest number of the labeled A431 cells detected by photoacoustic imaging and fluorescence imaging was 0 .4 × 106 and 0 .05 × 106 ,respectively . Conclusions The dual functional photoacoustic and fluorescence probe targeting integrin αvβ6 was successfully developed . The targeting and sensitivity of the probe makes it potentially useful in early detection of αvβ6 positive tumors .